September 2008 - Boost - lists.boost.org

[filesystem] has_branch_path()
by Robert Jones 23 Sep '08

23 Sep '08

I'm upgrading the Boost release in use at work from 1.33.1 to 1.36.0, with surprisingly few issues actually, but I am stuck on one thing. There's a function in 1.33.1, has_branch_path(), for which I cannot see the equivalent functionality in 1.36. Part of my difficulty is that the 1.33.1 header declares but does not define the function, and I cannot see where the body code is! Any suggestions would be appreciated at this point. Thanks. - Rob.

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Re: [boost] [Review] Phoenix review starts today, September 21st
by dan marsden 23 Sep '08

23 Sep '08

Joel de Guzman wrote: >Mathias Gaunard wrote: >> Joel de Guzman wrote: >> Isn't the move to first-class Boost citizen a good opportunity to change >> some parts of the interface, and thus give a new version number? > >Indeed. As noted in the review blurb, V3 will be the future of phoenix. >The V3 interface will be assumed. The most major interface shifts are: > >1) ET engine: Use of Boost.Proto >2) Result type deduction: Use of Boost.Typeof >3) Type deduction protocol: Use of Boost.Resultof > >As far as the interface goes, we can take all that for granted. >We have the proof of concept. > I think I'd add to your list of major interface shifts: 4) Extension protocol: The current extension approach is tightly coupled to the hand rolled expression templates, and will need changing for a proto based v3, unless if I've missed yet more genius from Eric? Cheers Dan

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[asio]Proper way to restart io_service
by Urberg, John 23 Sep '08

23 Sep '08

I have an application using boost::asio (v 1.35.0) that creates a udp multicast socket and an acceptor using an io_service and then calls io_service.run(). Additional sockets are created from acceptor.async_accept. My code needs to stop all the sockets and then restart them at a later point. When stopping the sockets, I close all the sockets I opened before deleting them. I then call io_service.stop(). When I restart things, I call io_service.reset(), recreate the udp multicast and acceptor sockets on the io_service and then call io_service.run(). When the io_service starts up again, it seems to have old operations on the queue and it tries to process them. I will usually get either a "vector iterator not dereferencable" error from a buffer on a deleted class or an error in a deleted version of the class that was processing async_accept before I stopped. Is there something additional I should be doing to clear the queue in the io_service? Thanks, John

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asio and shared libraries problem (linux only)
by Berserker 23 Sep '08

23 Sep '08

io_service and shared libraries problem (linux only) Short question: is it safe to share asio "objects" (io_services, sockets and so on...) across shared libraries/modules? Long story: we are porting our project from Windows to Linux (actually we are working on Ubuntu with GCC 4.2.3) and we discovered a problem when an io_service is shared between modules: creating an io_service, for example, in the main executable and passing that to a shared library causes on Linux problems with handler's invocation. I stress that on Windows we have never reported the problem (with and without IOCP defining BOOST_ASIO_DISABLE_IOCP), instead on Linux it's always reproducible (event disabling the epoll implementation with BOOST_ASIO_DISABLE_EPOLL). The following example can reproduce the problem: "test_working_asio_example" let the shared library to create the io_service and in this case the "handle_timeout" and "handle_connection" are invoked as expected, instead "test_not_working_asio_example" freezes in the io_service::run invocation because the timeout is never invoked. ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Shared library code: ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // connection.h //////////////////////////////////////////////////////////////////////////////////////////////////// #include <boost/asio.hpp> #include <boost/enable_shared_from_this.hpp> // NetExport on Windows is defined as _declspec(dllexport)/_declspec(dllimport) and on Linux is defined as __attribute__ ((visibility("default"))) class NetExport connection : public boost::enable_shared_from_this<connection> { public: connection(shared_ptr<boost::asio::io_service> service = shared_ptr<boost::asio::io_service>()); virtual ~connection(); boost::asio::io_service & service(); virtual void handle_connect(const boost::system::error_code &e); virtual void handle_timeout(); void connect(const boost::asio::ip::tcp::endpoint &endpoint, const boost::posix_time::time_duration &timeout); protected: shared_ptr<boost::asio::io_service> m_service; boost::asio::deadline_timer m_timeout; boost::asio::ip::tcp::socket m_socket; }; // connection.cpp //////////////////////////////////////////////////////////////////////////////////////////////////// #include "connection.h" #include <boost/bind.hpp> connection::connection(shared_ptr<boost::asio::io_service> service) : m_service(service ? service : shared_ptr<boost::asio::io_service>(new boost::asio::io_service())), m_timeout(*m_service), m_socket(*m_service) { std::cout << "connection::ctor" << std::endl; } connection::~connection() { std::cout << "connection::dctor" << std::endl; } boost::asio::io_service & connection::service() { return m_socket.io_service(); } void connection::handle_connect(const boost::system::error_code &e) { m_timeout.cancel(); if(e == boost::asio::error::operation_aborted) { std::cout << "connection::handle_connect (aborted)" << std::endl; return; } if(e) std::cout << "connection::handle_connect (error)" << std::endl; else std::cout << "connection::handle_connect (success)" << std::endl; } void connection::handle_timeout() { std::cout << "connection::handle_timeout" << std::endl; m_socket.close(); } void connection::connect(const boost::asio::ip::tcp::endpoint &endpoint, const boost::posix_time::time_duration &timeout) { m_socket.async_connect(endpoint, boost::bind(&connection::handle_connect, shared_from_this(), boost::asio::placeholders::error)); m_timeout.expires_from_now(timeout); m_timeout.async_wait(boost::bind(&connection::handle_timeout, shared_from_this())); } ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Main executable code: ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// void test_working_asio_example(const boost::asio::ip::tcp::endpoint &endpoint, const boost::posix_time::time_duration &timeout) { try { shared_ptr<connection> c(new connection()); c->connect(endpoint, timeout); c->service().run(); } catch(std::exception &e) { std::cerr << "Exception: " << e.what() << std::endl; } } void test_not_working_asio_example(const boost::asio::ip::tcp::endpoint &endpoint, const boost::posix_time::time_duration &timeout) { try { shared_ptr<connection> c(new connection(shared_ptr<boost::asio::io_service>(new boost::asio::io_service()))); c->connect(endpoint, timeout); c->service().run(); } catch(std::exception &e) { std::cerr << "Exception: " << e.what() << std::endl; } } int main(int argc, char *argv[]) { // 88.149.0.2:32123 is just a dummy endpoint that will "probably" timeout in 1 second ( if not try another fake one :) ) boost::asio::ip::tcp::endpoint endpoint(boost::asio::ip::address_v4::from_string("88.149.0.2"), 32123); boost::posix_time::time_duration timeout = boost::posix_time::seconds(1); test_working_asio_example(endpoint, timeout); test_not_working_asio_example(endpoint, timeout); return 0; } _________________________________________________________________ Stanco della solita finestra? 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bitmask operations (2)
by Arno Schödl 23 Sep '08

23 Sep '08

Sorry, _REGEX_BITMASK_OPS is from Dinkumware's library, so disregard:-( What is the boost way to define an enum enum EBitmask { ebitmaskFLAGA=1, ebitmaskFLAGB=2 }; such that operations like ebitmask |= ebitmaskFLAGA; can be used? In boost.regex, it is currently implemented specifically for match_flags: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) typedef unsigned long match_flag_type; #else typedef match_flags match_flag_type; #ifdef __cplusplus inline match_flags operator&(match_flags m1, match_flags m2) { return static_cast<match_flags>(static_cast<boost::int32_t>(m1) & static_cast<boost::int32_t>(m2)); } inline match_flags operator|(match_flags m1, match_flags m2) { return static_cast<match_flags>(static_cast<boost::int32_t>(m1) | static_cast<boost::int32_t>(m2)); } inline match_flags operator^(match_flags m1, match_flags m2) { return static_cast<match_flags>(static_cast<boost::int32_t>(m1) ^ static_cast<boost::int32_t>(m2)); } inline match_flags operator~(match_flags m1) { return static_cast<match_flags>(~static_cast<boost::int32_t>(m1)); } inline match_flags& operator&=(match_flags& m1, match_flags m2) { m1 = m1&m2; return m1; } inline match_flags& operator|=(match_flags& m1, match_flags m2) { m1 = m1|m2; return m1; } inline match_flags& operator^=(match_flags& m1, match_flags m2) { m1 = m1^m2; return m1; } #endif #endif Regards, Arno -- Dr. Arno Schoedl · aschoedl(a)think-cell.com Technical Director think-cell Software GmbH · Invalidenstr. 34 · 10115 Berlin, Germany http://www.think-cell.com · phone +49-30-666473-10 · toll-free (US) +1-800-891-8091 Directors: Dr. Markus Hannebauer, Dr. Arno Schoedl · Amtsgericht Charlottenburg, HRB 85229

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_REGEX_BITMASK_OPS in boost?
by Arno Schödl 23 Sep '08

23 Sep '08

_REGEX_BITMASK_OPS is used in the regex library to define binary operators for bitmask enums. I need something similar. What is the preferred way to do it? Should _REGEX_BITMASK_OPS be moved to a more public place? TIA, Arno -- Dr. Arno Schoedl · aschoedl(a)think-cell.com Technical Director think-cell Software GmbH · Invalidenstr. 34 · 10115 Berlin, Germany http://www.think-cell.com · phone +49-30-666473-10 · toll-free (US) +1-800-891-8091 Directors: Dr. Markus Hannebauer, Dr. Arno Schoedl · Amtsgericht Charlottenburg, HRB 85229

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[property tree] boost::filesystem::path
by Johan Råde 23 Sep '08

23 Sep '08

Currently there is a problem when you put and then get a boost::filesystem::path to/from a property tree. When you get the path, then the path is first read into a string. Then a stringstream is constructed, and the path is extracted from the stringstream. The problem is that when you extract a path from a stream and the path contains spaces, then the path is truncated at the first space. The solution may be to specialize struct boost::property_tree::detail::extractor for boost::filesystem::basic_path. Instead of using a stringstream you can directly convert a string to a path. --Johan Råde

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[metagraph] mpl_graph is now useable
by Gordon Woodhull 23 Sep '08

23 Sep '08

Hello - I recently posted to the sandbox a decent refactoring of the mpl_graph part of the Metagraph libraries I'm working on. mpl_graph is bgl-like graph metadata & metafunctions. Now there are two implementations - an adjacency list and an incidence list. That is, you can supply metadata in either of those formats and get full graph API access through metafunctions. Depth first search is also provided. Each capability that you access causes the library to create the corresponding indexing for the graph - that is, you pay for generating the relevant efficient metadata structure whenever you use a capability (or roughly, a concept). I think that each of the two previously reviewed libraries, FSM and Dataflow, could possibly benefit from mpl_graph. For FSM, this could be a nice input format, e.g. by supplying state data in the vertex types, and event action in the edge types. For the statically-generated Dataflow which Stjepan mentioned (not the version which was reviewed), a metadata graph could also be a nice input format, from which it would be possible to generate the call graph somewhat directly. Note that this allows templated functions to be called in combinatorial ways, generating some pretty complex code from a simple graph. But I'm getting ahead of myself (again). The big point is that there are all kinds of graphs in our code and data: generating code and data from metadata graphs is thus something we want to do. I'll work up some documentation once I get the doc toolchain working - in the meantime, please look at the examples, sandbox/metagraph/libs/metagraph/example/ I intend to do some profiling to see the complexity of the compile- time speed - it's noticeable but tolerable for small examples, on gcc. On msvc++, it's kinda slow, getting up toward a minute for a couple of examples. I don't yet know if this technique is viable for large compile-time graphs. mpl_graph is the first layer of the Metagraph stuff I've been going on about. This is just compile-time metadata graphs: mpl_graph is not the actual Metagraph compile-and-runtime data structure which started me on this quest, it's what makes that possible. Gordon

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[Signals] Build problem on Linux / ARM with GCC 3.4.4
by Tobias Oberstein 23 Sep '08

23 Sep '08

I'm trying to build Boost.Signals on a Debian-based (Nokia Maemo OS2008 Diablo) system which is using GCC 3.4.4 toolchain (CodeSourcery ARM 2005q3-2). Problem is when linking, I get duplicate symbol boost::exception_detail::make_clone<boost::exception_detail::error_info_injector<boost::bad_weak_ptr> >(boost::exception_detail::error_info_injector<boost::bad_weak_ptr> in trackable.o named_slot_map.o Details see below. Any hints? Thanks alot, tgo [sbox-DIABLO_ARMEL: ~/build/boost_1_36_0] > bjam --toolset=gcc --build-dir=/home/oberstet/tmp/boost --with-signals warning: Graph library does not contain optional GraphML reader. note: to enable GraphML support, set EXPAT_INCLUDE and EXPAT_LIBPATH to the note: directories containing the Expat headers and libraries, respectively. warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (don't panic: this is a strictly optional feature). ...patience... ...found 576 targets... ...updating 1 target... gcc.link.dll /home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/libboost_signals-gcc34-mt-1_36.so.1.36.0 /home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/named_slot_map.o:(.bss._ZZN5boost16exception_detail10make_cloneINS0_19error_info_injectorINS_12bad_weak_ptrEEEEEPNS0_10clone_baseERKT_E9bad_alloc[*boost::exception_detail::clone_base* boost::exception_detail::make_clone<boost::exception_detail::error_info_injector<boost::bad_weak_ptr> >(boost::exception_detail::error_info_injector<boost::bad_weak_ptr> const&)::bad_alloc]+0x0): multiple definition of `boost::exception_detail::clone_base* boost::exception_detail::make_clone<boost::exception_detail::error_info_injector<boost::bad_weak_ptr> >(boost::exception_detail::error_info_injector<boost::bad_weak_ptr> const&)::bad_alloc' /home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/trackable.o:(.bss._ZZN5boost16exception_detail10make_cloneINS0_19error_info_injectorINS_12bad_weak_ptrEEEEEPNS0_10clone_baseERKT_E9bad_alloc[boost::exception_detail::clone_base* boost::exception_detail::make_clone<boost::exception_detail::error_info_injector<boost::bad_weak_ptr> >(boost::exception_detail::error_info_injector<boost::bad_weak_ptr> const&)::bad_alloc]+0x0): first defined here collect2: ld returned 1 exit status "g++" -o "/home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/libboost_signals-gcc34-mt-1_36.so.1.36.0" -Wl,-h -Wl,libboost_signals-gcc34-mt-1_36.so.1.36.0 -shared -Wl,--start-group "/home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/trackable.o" "/home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/connection.o" "/home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/named_slot_map.o" "/home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/signal_base.o" "/home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/slot.o" -Wl,-Bstatic -Wl,-Bdynamic -lrt -Wl,--end-group -Wl,--strip-all -pthread ...failed gcc.link.dll /home/oberstet/tmp/boost/boost/bin.v2/libs/signals/build/gcc-3.4.4/release/threading-multi/libboost_signals-gcc34-mt-1_36.so.1.36.0... ...failed updating 1 target... [sbox-DIABLO_ARMEL: ~/build/boost_1_36_0] > g++ --version sbox-arm-linux-g++ (GCC) 3.4.4 (release) (CodeSourcery ARM 2005q3-2) Copyright (C) 2004 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. [sbox-DIABLO_ARMEL: ~/build/boost_1_36_0] >

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Compiling boost with visual c++
by Sean Farrow 22 Sep '08

22 Sep '08

Hi: Wha is the earliest visual c++ compuler the boost trunk will compile under? Chers Sean. __________ Information from ESET NOD32 Antivirus, version of virus signature database 3458 (20080921) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

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